1. Field
The present disclosure relates generally to aircraft and, in particular, to aircraft structures. Still more particularly, the present disclosure relates to stringers and other structural designs for an aircraft.
2. Background
Aircraft are being designed and manufactured with greater and greater percentages of composite materials. Some aircraft may have more than 50 percent of their primary structures made from composite materials. Composite materials may be used in aircraft to decrease the weight of the aircraft. This decreased weight may improve payload capacities and fuel efficiencies. Further, composite materials may provide longer service life for various components in an aircraft.
Composite materials may be tough, light-weight materials created by combining two or more dissimilar components. For example, a composite material may include fibers and resins. The fibers and resins may be combined to form a cured composite material.
Further, by using composite materials, portions of an aircraft may be created in larger pieces or sections. For example, a fuselage in an aircraft may be created in cylindrical sections that may be put together to form the fuselage of the aircraft. Other examples may include, without limitation, wing sections joined to form a wing or stabilizer sections joined to form a stabilizer.
A stringer is an example of a component that may be manufactured from composite materials. A stringer is an elongate member and is configured for attachment to another structure, such as a panel. For example, a stringer may be attached to a skin panel for an aircraft. This skin panel may be used in a wing, fuselage, or other component in the aircraft. The stringer also may help carry and/or transfer loads. For example, a stringer may transfer a load from a skin panel to another structure. This other structure may be, for example, a frame or a rib.
Designing stringers with a desired weight and performance characteristics may be challenging. For example, a stringer with desired performance characteristics may be more complex or weigh more than desired. With increased complexity, time and cost for manufacturing a stringer also may increase. Further, if the stringer has a desired weight, performance characteristics may be such that additional stringers may be required where a single stringer is desired. Therefore, it would be desirable to have a method and apparatus that takes into account at least some of the issues discussed above, as well as possibly other issues.